Relatively large reusable containers are utilized by manufacturers to ship a variety of different products to their customers. For example, in the automobile industry, a plant assembling a particular automobile might utilize a number of different parts manufacturers. These manufacturers ship their respective parts to the plant in reusable containers where the parts are then assembled together into a finished automobile. The reusable containers are often returned to the parts manufacturers for use in further shipments, thus saving the manufacturers cost of the containers.
The construction of some such shipping containers includes a pallet base, a cover and a rectangular sleeve pack which is situated between the base and the cover to form the sidewalls and body of the container. Such a design provides a versatile and lightweight shipping container which may be reused time and time again. Such a container is commonly referred to as a sleeve pack assembly with the sleeve pack sandwiched between the cover and the pallet base. The vast majority of sleeve packs used today are made of heavy grades of triple ply corrugated paper or corrugated plastic.
As outdoor storage containers, plastic sleeve packs have been manufactured and utilized as weatherproof containers. However, both the plastic and paperboard existing sleeve packs have undesirable limitations. One of the potential problems with existing sleeve packs is the lack of ability of the sleeve pack walls to carry heavy vertical loads such as occurs when loaded sleeve packs are stacked one upon the other.
One of the methods utilized to increase the vertical strength or resistance to vertical collapse of the sleeve pack sidewalls has been to reinforce the sleeve pack sidewalls with steel rods commonly referred to in the industry as flute rods. Flute rods are inserted between adjacent vertically-oriented corrugations in the sidewalls of sleeve packs when the sleeve pack sidewalls are made of double face corrugated paper or plastic. Each sidewall has a plurality of vertically oriented corrugations, two adjacent corrugations defining a flute. The flute rods are inserted into the flutes of the sidewalls and provide the sidewalls of the sleeve pack additional strength to withstand both horizontal and vertical impacts.
The flute rods used to reinforce the sidewalls of a sleeve pack have heretofore been straight steel rods. One of the potential problems with inserting straight flute rods into the flutes of the sidewalls of the sleeve pack is that the flute rods would pass downwardly through the flutes of the sidewall when the sleeve pack was lifted away from the pallet base. If the sleeve pack were inverted the flute rods would fall out the top end rather than the bottom end of the sleeve pack sidewall. This made assembly and reuse of sleeve packs having flute rod reinforced sidewalls difficult, costly and frustrating.
To prevent the flute rods from falling from the flutes of the sleeve pack, the rods have in the past have been permanently secured therein. One technique used to secure the flute rods within the flutes of the sidewalls of a sleeve pack has been to inject a hot melt adhesive into the flutes located between the two faces of a sidewall of a sleeve pack so that the adhesive ran down the flutes between the two faces of the sidewalls between adjacent corrugations. Immediately after the hot melt adhesive has been inserted into the flutes, the flute rods are pressed down into the flutes filled with adhesive from the top edge of the sidewall.
One problem with this method of adhesively securing the flute rods inside the sleeve pack sidewalls has been that often the hot melt adhesive set up or hardened before all of the flute rods could be installed. Having the partially hardened adhesive located in the flutes of the sidewalls between the corrugations required that someone pound the flute rods down into the flutes of the sidewalls of the sleeve pack usually with a hammer or mallet.
Another potential problem with using adhesive to secure the flute rods inside the flutes of the sidewalls is that the hot adhesive may splatter and burn the operator. The adhesive may also splash onto the exterior of the sleeve pack and once hardened be difficult to remove. This method of securing the flute rods within the flutes filled with adhesive has therefore been relatively dangerous, messy, cumbersome and costly.
It has therefore been an objective of the present invention to provide a sleeve pack with flute rod reinforced sidewalls in which the flute rods are secured in the sidewalls of the sleeve pack in a safe, reliable and efficient manner.
It has been another objective of the present invention to provide a sleeve pack with flute rod reinforced sidewalls wherein the flute rods may not fall out of the sidewalls, enabling the sleeve packs to be conventionally reused.
It has been another objective of the present invention to provide a method of reinforcing sleeve pack sidewalls with vertically oriented flute rods which are secured in the sleeve pack sidewalls without the use of any adhesive within the flutes or internal fasteners.